In recent years, suppression of energy consumption has been required in factories, offices (buildings), and homes. According to statistical data of the energy consumption, the proportion of the energy consumption in homes is relatively high in total energy consumption. Therefore, the suppression of the energy consumption in homes is an issue to be addressed. A technology of controlling energy in homes is called a “home energy management system” (HEMS). The conventional HEMS implements measures for energy conservation including on/off control of electrical appliances such as an air conditioner, collection of logs of power consumption, and the like.
Meanwhile, power generation using renewable energy in place of fossil fuel is being put to practical use, and it is expected, in the future, this tendency becomes stronger. As the power generation using the renewable energy, solar power generation, wind power generation, biomass power generation, wave activated power generation, and the like have been developed. Actually, it has been spread that a solar panel is disposed on a roof, a wall, and the like, and the solar power generation is performed in each home.
It can be considered that power by the solar power generation is stored in a storage battery disposed in each home and the power is supplied to a load in the home. In this case, the power consumed by electrical appliances in the home is mixed power from an existing power supply network and from the storage battery. The storage battery is charged with the power by the renewable energy or with the power from the power supply network. Further, even the power from the power supply network is mixed power generated by different power generation methods such as thermal power generation, nuclear power generation, and the like.
The conventional measurements to suppress consumed electric energy in the home do not focus on the origin of the power, and therefore, have a problem of not necessarily leading to the reduction of a CO2 (carbon dioxide) emission amount. As disclosed in Patent Document 1, a system of managing the CO2 emission amount is proposed. In Patent Document 1, the CO2 emission amount is obtained for each site, the CO2 emission amount of each site is collected by a management device, and whether the CO2 emission amount is a target value or less by each device group in each site is determined.